Where does the right thoracic duct collect lymph? Lymph
Thoracic duct I
Thoracic duct (ductus throracicus)
the main lymphatic collector that collects lymph from most of the human body and drains into the venous system. The G. p. passes only, flowing from the right half of the chest, head, neck and right upper limb - it flows into the right. The length of the glans in an adult is about 40 cm, diameter about 3 mm. The duct is formed in the retroperitoneal tissue at the level of THXII - L II vertebrae by the fusion of large lymphatic trunks. The initial part of the duct () is wide - with a diameter of 7-8 mm. G. p. passes through the diaphragm to the back and is located between the descending aorta and the azygos vein. Then G. p .
deviates to the left and the aortic arch emerges from under the left edge of the esophagus, slightly above the left clavicle it bends in an arcuate manner and flows into the venous bed at the confluence of the left subclavian and internal jugular veins. In the thoracic duct, incl. at its entry into the venous system, there are valves that prevent blood from flowing into it. The main method of studying G. p. is contrast lymphography .
It is performed by slowly injecting superfluid iodolipol or myodil into the lymphatic vessels of one or both feet. G.'s pathology is rare in clinical practice. Gp are of greatest importance for open and especially closed chest injuries, as well as for various operations on the neck and chest cavity. G. p. may be accompanied by external outflow of chyle (external chylorea) or outflow of chyle into the pleural cavity (). The characteristic clinical manifestations of chylothorax are caused mainly by compression of the lung, displacement of the mediastinum with symptoms of respiratory failure (Respiratory failure) and hemodynamic disturbances. The right-sided chylothorax is more pronounced than the left-sided one, which is associated with greater compliance of the left dome of the diaphragm and less pronounced displacement of organs due to the accumulation of chyle in the left pleural cavity. In this case, there is a risk of damage to the recurrent, vagus and phrenic nerves.
1. Small medical encyclopedia. - M.: Medical encyclopedia. 1991-96 2. First aid. - M.: Great Russian Encyclopedia. 1994 3. Encyclopedic Dictionary of Medical Terms. - M.: Soviet Encyclopedia. - 1982-1984.
Veterinary encyclopedic dictionary
thoracic duct- (ductus thoracicus) is the largest lymphatic vessel, 30–40 cm long. It is formed in the upper abdominal cavity from the confluence of the right and left lumbar trunks. According to the length of the thoracic duct, the abdominal, thoracic and cervical parts are distinguished. IN… … Glossary of terms and concepts on human anatomy
One of the two main lymphatic ducts. Lymph passes through it from both lower extremities, from the lower abdomen, the left half of the chest and head, as well as from the left arm. The thoracic duct drains into the left venous angle.
thoracic duct, ductus thoracicus , is formed in the abdominal cavity, in the retroperitoneal tissue, at the level of the XII thoracic - II lumbar vertebrae as a result of fusion right and left lumbar lymphatic trunks,trunci lumbales dexter et sinister.
Formation of the thoracic duct
These trunks are formed from the fusion of the efferent lymphatic vessels of the right and left lumbar lymph nodes, respectively.
One to three efferent lymphatic vessels of the mesenteric lymph nodes, which are called intestinal trunks,trunci intestinales. prevertebral, intercostal, as well as visceral (preaortic) lymph nodes of the thoracic cavity.
abdominal part,pars abdominalis, The thoracic duct is its initial part. It has an extension - thoracic duct cistern,cisterna chyli.
chest part,pars thoracica, the longest. It extends from the aortic opening of the diaphragm to the superior thoracic aperture, where the duct enters its cervical part,pars cervicalis.
Arc of the thoracic duct
arcus ductus thoracici, bends around the dome of the pleura from above and behind, and then the mouth of the duct opens into the left venous angle or into the terminal section of the veins that form it. In approximately 50% of cases, the thoracic duct is dilated before entering the vein. The duct also often bifurcates, and in some cases flows into the veins of the neck with three or four stems.
At the mouth of the thoracic duct there is a paired valve that prevents the flow of blood from the vein. The wall of the thoracic duct, in addition to the inner membrane, tunica interna, and outer shell, tunica externa, contains the middle (muscular) layer, tunica media.
In approximately a third of cases, duplication of the lower half of the thoracic duct occurs: next to its main trunk there is an accessory thoracic duct. Sometimes local splitting (doubling) of the thoracic duct is found.
The thoracic duct of the lymphatic system plays the role of one of the main lymphatic “collectors”, which transports lymphatic fluid from:
All abdominal organs.
Both legs.
Small pelvis.
Left parts of the upper limb.
Some parts of the heart.
Lateral sections of the head and neck.
Thoracic lymphatic duct system
Its length is about 34 - 45 centimeters, and the diameter of the lumen varies throughout its entire length. The vessel includes two expansions: one at the very beginning and the second begins closer to the end of the duct.
It is formed due to the union of a group of lymphatic vessels at the level of the second lumbar vertebra. At the beginning there is a small thickening - the thoracic duct cistern. It is worth noting that the boundaries of its beginning, as well as the presence of the initial expansion, its size and shape are individual characteristics and in some cases may change (features of formation during the period in the womb or as a consequence of secondary pathological processes).
According to topographic criteria, the duct is divided into thoracic, abdominal, and cervical parts.
Thoracic lymphatic duct
In this section, the duct is located in the posterior mediastinum, between the aorta and azygos vein with a transition to the anterior surface of the vertebrae. Further, it goes upward and, at the level of the third thoracic vertebra, is located on the left side in relation to the esophagus and so follows until the seventh cervical vertebra.
It may be bifurcated, but by the time it enters the abdominal part it will unite back together. In this part of the duct, the following begin to be added to its composition:
Lymphatic vessels of small and medium caliber emerging from the intercostal spaces.
Bronchomediastinal trunk.
Cervical region - begins from the seventh cervical vertebra and branches in the fiber.
Abdominal thoracic duct
The lumbar and intestinal trunks are the main efferent vessels that collect intercellular fluid from the corresponding regional lymph nodes after its preliminary purification. After this, they both go to the thoracic duct cistern and flow into it, thereby forming the abdominal part.
Functions of the lymphatic duct
The main function of this anatomical structure is to transport the bodice, which has been previously cleared in the lymph nodes, and return it back to the bloodstream by transporting it to the venous angle. The flow of lymphatic fluid is carried out thanks to:
1. Pressure differences between large venous vessels and the chest cavity.
2. Due to the presence of valves in the duct itself.
3. Due to the compressive action of the diaphragmatic legs.
Methods for studying the lymphatic duct
A modern method for assessing the condition of the thoracic duct, its patency, and integrity is lymphangiography using X-ray contrast agents.
The technique consists of introducing an X-ray contrast agent through access, in this case an iodine-containing drug (myodil, urografin, etc.). After which an x-ray examination is performed. In the image, thanks to the contrast, the corresponding anatomical structure, its contours, real sizes, narrowings, expansions, etc. will be visible.
What diseases can be associated with damage to the lymphatic duct?
In modern realities, damage to the thoracic duct as a result of any disease is an extremely rare case and is practically not observed in everyday practice. Another thing is damage to this structure during traumatic lesions of the chest, both open and closed injuries, or during surgical interventions in the neck or on organs located close to the site of the main branches of the duct.
As a result of damage to the duct, external or internal chylorrhea develops (the contents begin to flow either outward or begin to fill the free cavities inside the body).
The most dangerous condition resulting from vessel trauma is chylothorocas - the release of contents into the pleural cavity.
Characterized by:
Difficulty breathing.
Retention of one of the halves of the chest during the act of breathing.
Increasing respiratory failure.
Changes in the blood circulation system.
Development of acidosis.
Quite often one can observe inflammation of the walls of the thoracic duct of the lymphatic system in patients with tuberculosis infection or filariasis. The result is swelling of the duct wall, which leads to narrowing of the vessel and, as a consequence, obstruction of patency. What can lead to development:
1. Hiluria.
2. Chylothorax.
3. Chylopericardium.
4. Chyloperitoneum.
Malignant and benign neoplasms can disrupt lymphodynamics by compressing the lymphatic vessels, as a result of prolonged compression and obstruction of patency, the contents of the duct may leak into the pleural cavity or into the abdominal cavity (development of chyloperitoneum). In such cases, surgery is urgently needed.
Treatment
Treatment of various lesions of the thoracic lymphatic duct is primarily focused on:
Elimination of the underlying disease that led to impaired lymphodynamics.
Restoration of vessel patency and integrity.
Elimination of hilorrhea.
Removal of residual lymph from all cavities.
Carrying out detoxification therapy.
Initially, conservative and minimally invasive treatment methods are used. To eliminate the leakage of the lypha, the patient is transferred to parenteral nutrition (iv solutions of amino acids, glucose, etc.) for a period of 10 to 15 days.
If lymph flows into the pleural cavity, aspiration drainage of this cavity is performed.
If such treatment is ineffective, it is necessary to proceed with measures aimed at restoring the natural flow of lymph by ligating the lymph duct above and below the interruption site, followed by an attempt to restore the vascular wall at the site of deformation.
Video: mammary gland lymphatic drainage
After the lymph has passed through the lymph nodes, it is collected in lymphatic trunks And lymphatic ducts. A person has six such large trunks and ducts. Three of them flow into the right and left venous angles.
The main and largest lymphatic vessel is the thoracic duct. The thoracic duct carries lymph from the lower extremities, organs and walls of the pelvis, the left side of the chest cavity and the abdominal cavity. Through the right subclavian trunk, lymph flows from the right upper limb into the right jugular trunk from the right half of the head and neck. From the organs of the right half of the thoracic cavity, lymph flows into the right bronchomediastinal trunk, which flows into the right venous angle or into the right lymphatic duct. Accordingly, through the left subclavian trunk, lymph flows from the left upper limb, and from the left half of the head and neck through the left jugular trunk, from the organs of the left half of the thoracic cavity, lymph flows into the left bronchomediastinal trunk, which flows into the thoracic duct.
Thoracic lymphatic duct
The formation of the thoracic duct occurs in the abdominal cavity, in the retroperitoneal tissue at the level of the 12th thoracic and 2nd lumbar vertebrae during the connection of the right and left lumbar lymphatic trunks. The formation of these trunks occurs as a result of the fusion of the efferent lymphatic vessels of the right and left lumbar lymph nodes. From 1 to 3 efferent lymphatic vessels belonging to the mesenteric lymph nodes, called intestinal trunks, flow into the initial part of the thoracic lymphatic duct. This is observed in 25% of cases.
The lymphatic efferent vessels of the intercostal, prevertebral and visceral lymph nodes flow into the thoracic duct. Its length is from 30 to 40 cm.
The initial part of the thoracic duct is its abdominal part. In 75% of cases, it has an ampulla-shaped, cone-shaped or spindle-shaped expansion. In other cases, this beginning is a reticular plexus, which is formed by the efferent lymphatic vessels of the mesenteric, lumbar and celiac lymph nodes. This expansion is called a tank. Usually the walls of this tank are fused with the right leg of the diaphragm. During breathing, the diaphragm compresses the thoracic duct, facilitating the flow of lymph.
The thoracic lymphatic duct from the abdominal cavity enters the chest cavity through the aortic opening and penetrates the posterior mediastinum. There it is located on the anterior surface of the spinal column, between the azygos vein and the thoracic aorta, behind the esophagus.
The thoracic part of the thoracic duct is the longest. It originates at the aortic opening of the diaphragm and goes to the upper thoracic aperture, passing into the cervical part of the duct. In the region of the 6th and 7th thoracic vertebrae, the thoracic duct deviates to the left and emerges from under the left edge of the esophagus at the level of the 2nd and 3rd thoracic vertebrae, rising up behind the left subclavian and left common carotid artery and the vagus nerve. In the superior mediastinum, the thoracic duct passes between the left mediastinal pleura, the esophagus and the vertebral column. The cervical part of the thoracic lymphatic duct has a bend, forming an arch at the level of 5-7 cervical vertebrae, which bends around the dome of the pleura from above and slightly behind, and then opening at the mouth into the left venous angle or into the terminal section of the veins that form it. In half of the cases, the thoracic lymphatic duct expands before entering the vein; in some cases, it bifurcates or has 3-4 stems flowing into the venous angle or into the terminal sections of the veins that form it.
The passage of blood from the vein into the duct is prevented by a paired valve located at the mouth of the thoracic lymphatic duct. Also along the entire length of the thoracic duct there are from 7 to 9 valves that prevent the reverse movement of lymph. The walls of the thoracic duct have a muscular outer shell, the muscles of which promote the movement of lymph to the mouth of the duct.
In some cases (approximately 30%), the lower half of the thoracic duct is duplicated.
Right lymphatic duct
The right lymphatic duct is a vessel with a length of 10 to 12 mm. The bronchomediastinal trunk, jugular trunk and subclavian trunk flow into it. It has on average 2-3 sometimes more trunks flowing into the angle formed by the right subclavian vein and the right internal jugular vein. In rare cases, the right lymphatic duct has one mouth.
Jugular trunks
The right and left jugular trunks originate in the efferent lymphatic vessels of the lateral deep cervical right and left lymph nodes. Each consists of one vessel or several short ones. The right jugular trunk enters the right venous angle, the terminal part of the right internal jugular vein, or forms the right lymphatic duct. The left jugular trunk enters the left venous angle, the internal jugular vein, or the cervical part of the thoracic duct.
Subclavian trunks
The right and left subclavian trunks originate from the efferent lymphatic vessels belonging to the axillary lymph nodes, most often the apical ones. These trunks go to the right and left venous angle, respectively, in the form of one trunk or several small ones. The right subclavian lymphatic trunk flows into the right venous angle, or into the right subclavian vein, the right lymphatic duct. The left subclavian lymphatic trunk drains into the left venous angle, the left subclavian vein, and in some cases it drains into the terminal part of the thoracic duct.
The right lymphatic duct, ductus lymphaticus dexter, has a length of no more than 10-12 mm and is formed from the fusion of three trunks: truncus jugularis dexter, receiving lymph from the right region of the head and neck, truncus subclavius dexter, carrying lymph from the right upper limb, and truncus bronchomediastinalis dexter , which collects lymph from the walls and organs of the right half of the chest and the lower lobe of the left lung. The right lymphatic duct drains into the right subclavian vein. Very often it is absent, in which case the three trunks listed above independently flow into the subclavian vein
4. Spinal cord: external structure, topography The spinal cord, medulla spinalis (Fig. 878, 879), compared to the brain, has a relatively simple structural principle and a pronounced segmental organization. It provides connections between the brain and the periphery and carries out segmental reflex activity.
The spinal cord lies in the spinal canal from the upper edge of the first cervical vertebra to the first or upper edge of the second lumbar vertebra, repeating to a certain extent the direction of curvature of the corresponding parts of the spinal column. In a 3-month-old fetus it ends at the level of the V lumbar vertebra, in a newborn - at the level of the III lumbar vertebra.
The spinal cord, without a sharp boundary, passes into the medulla oblongata at the site of exit of the first cervical spinal nerve. Skeletotopically, this boundary passes at the level between the lower edge of the foramen magnum and the upper edge of the first cervical vertebra. Below, the spinal cord passes into the medullary cone, conus medullaris, which continues into the filum terminate (spinate), which has a diameter of up to 1 mm and is a reduced part of the lower part of the spinal cord. The filum terminale, with the exception of its upper sections where there are elements of nervous tissue, is a connective tissue formation. Together with the dura mater of the spinal cord, it penetrates the sacral canal and attaches at its end. That part of the filum terminates, which is located in the cavity of the dura mater and is not fused with it, is called the internal filum terminate internum; the rest of its part, fused with the dura mater, is the external terminal filum (dura), filum terminale externum (durale). The filum terminale is accompanied by the anterior spinal arteries and veins, as well as one or two roots of the coccygeal nerves.
The spinal cord does not occupy the entire cavity of the spinal canal: between the walls of the canal and the brain there remains a space filled with fatty tissue, blood vessels, meninges and cerebrospinal fluid.
The length of the spinal cord in an adult ranges from 40 to 45 cm, width - from 1.0 to 1.5 cm, and weight is on average 35 g.
There are four surfaces of the spinal cord: a slightly flattened anterior surface, a slightly convex posterior surface, and two lateral, almost rounded surfaces, passing into the anterior and posterior.
The spinal cord does not have the same diameter throughout. Its thickness increases slightly from bottom to top. The largest size in diameter is observed in two fusiform thickenings: in the upper section - this is the cervical thickening, intumescentia cervicalis, corresponding to the exit of the spinal nerves going to the upper limbs, and in the lower section - this is the lumbosacral thickening, intumescentia lumbosacralis, - the place where the nerves exit to lower limbs. In the area of the cervical thickening, the transverse size of the spinal cord reaches 1.3-1.5 cm, in the middle of the thoracic part - 1 cm, in the area of the lumbosacral thickening - 1.2 cm; the anteroposterior size in the area of thickenings reaches 0.9 cm, in the thoracic part - 0.8 cm.
The cervical thickening begins at the level of the III-IV cervical vertebra, reaches the II thoracic vertebra, reaching its greatest width at the level of the V-VI cervical vertebra (at the height of the fifth-sixth cervical spinal nerve). The lumbosacral thickening extends from the level of the IX-X thoracic vertebra to the I lumbar vertebra, its greatest width corresponds to the level of the XII thoracic vertebra (at the height of the third lumbar spinal nerve).
The shape of cross sections of the spinal cord at different levels is different: in the upper part the section has the shape of an oval, in the middle part it is round, and in the lower part it is close to square.
On the anterior surface of the spinal cord, along its entire length, lies a deep anterior median fissure, fissura mediana ventralis (anterior) (Fig. 880-882, see Fig. 878), into which a fold of the pia mater is invaginated - the intermediate cervical septum, septum cervical intermedium. This gap is less deep at the upper and lower ends of the spinal cord and is most pronounced in its middle parts.
On the posterior surface of the brain there is a very narrow posterior median groove, sulcus medianus dorsalis, into which a plate of glial tissue penetrates - posterior median septum, septum medianum dorsale. The fissure and groove divide the spinal cord into two halves - right and left. Both halves are connected by a narrow bridge of brain tissue, in the middle of which is the central canal, canalis centralis, of the spinal cord.
On the lateral surface of each half of the spinal cord there are two shallow grooves. The anterolateral groove, sulcus ventrolateralis, is located outward from the anterior median fissure, more distant from it in the upper and middle parts of the spinal cord than in its lower part. The posterolateral sulcus, sulcus dorsolateralis, lies outward from the posterior median sulcus. Both grooves run almost the entire length of the spinal cord.
In the cervical and partly in the upper thoracic regions, between the posterior median and posterolateral grooves, there is a faint posterior intermediate groove, sulcus intermedius dorsalis (see Fig. 881).
In the fetus and newborn, a rather deep anterior intermediate sulcus is sometimes found, which, following the anterior surface of the upper cervical part of the spinal cord, is located between the anterior median fissure and the anterolateral sulcus.
The anterior radicular filaments, fila radicularia, which are processes of motor cells, emerge from the anterolateral groove or near it. The anterior radicular filaments form the anterior root (motor), radix ventralis (motoria). The anterior roots contain centrifugal (efferent) fibers that conduct motor and autonomic impulses to the periphery of the body: to striated and smooth muscles, glands, etc.
The posterolateral groove includes the dorsal root filaments, consisting of processes of cells located in the spinal ganglion. The posterior radicular filaments form the posterior root (sensitive), radix dorsalis. The dorsal roots contain afferent (centripetal) nerve fibers that conduct sensitive impulses from the periphery, i.e., from all tissues and organs of the body, to the central nervous system.
The spinal node (sensitive), ganglion spinale (see Fig. 879, 880), is a fusiform thickening located on the dorsal root. It is a collection of mainly pseudounipolar nerve cells. The process of each such cell is divided T-shaped into two processes: the long peripheral one is directed to the periphery as part of the spinal nerve, n. spinalis, and ends in a sensory nerve ending; the short central one follows as part of the dorsal root into the spinal cord (see Fig. 947). All spinal nodes, with the exception of the coccygeal root node, are tightly surrounded by the dura mater; the nodes of the cervical, thoracic and lumbar regions lie in the intervertebral foramina, the nodes of the sacral region - inside the sacral canal.
Ascending tracts of the spinal cord and brain; right hemisphere (semi-schematic).
The direction of the roots is not the same: in the cervical region they extend almost horizontally, in the thoracic region they are directed obliquely downwards, in the lumbosacral region they go straight down (see Fig. 879).
The anterior and posterior roots of the same level and one side immediately outside the spinal ganglion are connected, forming the spinal nerve, n. spinalis, which is therefore mixed. Each pair of spinal nerves (right and left) corresponds to a specific area - segment - of the spinal cord.
Consequently, the spinal cord has as many segments as there are pairs of spinal nerves.
The spinal cord is divided into five parts: the cervical part, pars cervicalis, the thoracic part, pars thoracica, the lumbar part, pars lumbalis, the sacral part, pars sacralis, and the coccygeal part, pars coccygea (see Fig. 879). Each of these parts includes a certain number of segments of the spinal cord, segmenta medullae spinalis, i.e. sections of the spinal cord that give rise to one pair of spinal nerves (right and left).
The cervical part of the spinal cord consists of eight cervical segments, segmenta medullae spinalis cervicalia, the thoracic part - 12 thoracic segments, segmenta medullae spinalis thoracicae, the lumbar part - five lumbar segments, segmenta medullae spinalis lumbalia, the sacral part - five sacral segments, segmenta medullae spinalis sacralia, and finally, the coccygeal part consists of one to three coccygeal segments, segmenta medullae spinalis coccygea. Total 31 segments.
outer base of the skull, sections
The occipital bone, posterior surfaces of the pyramids, and temporal bones take part in the formation of the posterior cranial fossa.
Between the back of the sella turcica and the foramen magnum there is a clivus.
The internal auditory foramen (right and left) opens into the posterior cranial fossa, from which the vestibulocochlear nerve (VIII pair) emerges, and from the facial nerve canal - the facial nerve (VII pair). The lingual pharyngeal (IX pair), vagus (X pair) and accessory (XI pair) nerves exit through the jugular foramen of the base of the skull. The nerve of the same name, the XII pair, passes through the canal of the hypoglossal nerve. In addition to the nerves, the internal jugular vein emerges from the cranial cavity through the jugular foramen, which passes into the sigmoid sinus. The formed foramen magnum connects the cavity of the posterior cranial fossa with the spinal canal, at the level of which the medulla oblongata passes into the spinal cord.
The outer base of the skull (basis cranii extema) in its anterior section is covered by the facial bones (it contains a bony palate, limited in front by the alveolar process of the upper jaw and teeth), and the posterior section is formed by the outer surfaces of the sphenoid, occipital and temporal bones
This area has a large number of openings through which vessels and nerves pass, providing blood supply to the brain. The central part of the external base of the skull is occupied by the foramen magnum, on the sides of which are the occipital condyles. The latter connect to the first vertebra of the cervical spine. The exit from the nasal cavity is represented by paired openings (choanae), which pass into the nasal cavity. In addition, on the outer surface of the base of the skull there are the pterygoid processes of the sphenoid bone, the external opening of the carotid canal, the styloid process, the stylomastoid foramen, the mastoid process, the myotubal canal, the jugular foramen and other formations.
In the skeleton of the facial skull, the central place is occupied by the nasal cavity, orbits, oral cavity, infratemporal and pterygopalatine fossa
2.hard and soft palate
The oral cavity itself is limited above by the hard palate and part of the soft palate, below by the tongue along with the muscles that form the floor of the mouth, in front and on the sides by the dentition and gums. The posterior boundary of the cavity is the soft palate with the uvula, which separates the mouth from the pharynx. In newborns, the oral cavity is short and low due to the absence of teeth. As the dentofacial apparatus develops, it gradually acquires a definitive volume. In mature people, the shape of the oral cavity has individual characteristics. In short-headed animals it is wider and higher than in long-headed ones.
Depending on the shape of the hard palate and the height of the alveolar processes, the vault (dome) formed by the upper wall of the oral cavity can be of different heights. In people with a narrow and high face (dolichocephalic type), the vault of the palate is usually high, in people with a wide and low face (brachycephalic type), the vault of the palate is flattened. It has been observed that people with a singing voice have a higher vault of the palate. With an increased volume of the oral cavity, one of the resonator cavities is the physical basis for the development of vocal abilities.
The soft palate hangs freely, fixed at the top along the bony elements of the hard palate. During quiet breathing, it separates the oral cavity from the pharynx. At the moment of swallowing food, the soft palate is set horizontally, separating the oropharynx from the nasopharynx, i.e., isolating the alimentary tract from the respiratory tract. The same thing happens when gagging movements are realized. The mobility of the soft palate is ensured by its muscles, which are able to strain, raise and lower it. The action of this muscle is automatic.
The floor of the mouth, or its lower base, consists of soft tissues, the support of which is mainly the mylohyoid and mental muscles.
The functions of the mouth are regulated by a complex nervous system in which nerve fibers take part: motor secretory, sensory and gustatory.
The oral cavity performs a variety of physiological functions: here food is subjected to mechanical grinding, and here it begins to undergo chemical processing (exposure to saliva). With the help of ptyalin contained in saliva, the saccharification of starchy substances begins. The soaking and enveloping of saliva makes tough foods easier to swallow; without saliva, swallowing would not be possible. The work of the salivary glands is closely related to stimuli in the external environment and is an innate unconditioned reflex. In addition to this unconditioned reflex, salivation can also be a conditioned reflex, that is, saliva can be released when there is an irritant coming from the eye - light, ear - acoustic, skin - tactile.
Excitation of the nervous apparatus of the salivary glands, i.e. increased salivation, can occur when certain chemicals (for example, pilocarpine) enter the oral cavity, during various inflammatory processes in the oral cavity (for example, with stomatitis), when other organs are damaged (for example, stomach, intestines), with trigeminal neuralgia. Inhibition of the nervous apparatus of the salivary glands, i.e., a decrease in salivation, occurs under the influence of certain chemicals (atropine) and under the influence of reflex moments (fear, excitement).
The oral cavity is a control point where nutrients are checked using the senses of taste and smell. The numerous taste buds on the tongue contain fibers of the taste nerve. With indigestion, the patient feels a bad taste in the mouth, the tongue becomes coated and coated. According to Pavlov, this is a self-healing reflex on the part of the body; a reflex arises in the intestine, which is transmitted to the tongue through trophic nerves, causing loss of taste, i.e. abstinence from food, thereby ensuring peace in the digestive canal.
The first act of swallowing occurs in the oral cavity. When sucking, the soft palate descends and closes the oral cavity from behind; in front, the oral cavity is closed by the action of m. orbicularis oris, which extends the baby’s lips around the nipple or horn like a trunk. With a cleft lip, the integrity of m. The orbicularis oris is disrupted, and the act of sucking becomes difficult.
The sucking act can continue indefinitely, since when the velum is lowered, nasal breathing occurs normally.
During the act of swallowing, the root of the tongue descends, the soft palate rises to a horizontal position, separating the nasopharynx cavity from the oral cavity. The tongue pushes food into the funnel formed. At the same time, the glottis closes, food comes into contact with the walls of the pharynx, causing contraction of the pharyngeal muscles and constrictors, which push the bolus of food further into the esophagus.
The oral cavity is involved in speech: without the participation of the tongue, speech is impossible. During phonation, the soft palate, rising and falling, regulates the nasal resonator. This explains the complications during sucking, swallowing and phonation that lead to cleft palate defects, paralysis of the velum, etc.
The oral cavity also serves for breathing.
There is always a large number of microorganisms and their associations in the oral cavity. These various microbes, mixing with saliva and food debris, cause a number of chemical processes in the mouth, deposition of stone on the teeth, in the glands, etc. Hence the need for oral hygiene becomes clear.
3) Superior vena cava and brachiocephalic veins
The brachiocephalic and superior vena cava are located in the tissue of the anterior mediastinum directly behind the thymus, and the superior vena cava, in addition, lies behind the anteromedial part of the right mediaetinal pleura, and below - inside the pericardial cavity. The right and left brachiocephalic veins are formed from the confluence of the corresponding subclavian and internal jugular veins behind the sternoclavicular joints.
V. brachiocephalica dextra is located behind the right half of the manubrium of the sternum, extending from the right sternoclavicular joint to the attachment of the cartilage of the first rib to the sternum, where the right and left brachiocephalic veins, merging with each other, form the superior vena cava. The mednastinal pleura is adjacent to the anterior externally inferior part of the right brachiocephalic vein, especially if it is long, and to its lateral surface. The right phrenic nerve passes between the pleura and the vein. Posterior and medial to the right brachiocephalic vein lies the brachiocephalic trunk, and posteriorly lies the right vagus nerve.
V. brachiocephalica sinistra is located transversely or obliquely behind the manubrium of the sternum, projecting from the left sternoclavicular joint to the junction of the cartilage of the right first rib with the sternum or at any point below, to the level of attachment of the upper edge of the second costal cartilage to the sternum. The thymus gland is adjacent to the vein in front, the aortic arch, brachiocephalic trunk and left common carotid artery are behind, and the perinard is below. V. intercostalis superior sinistra flows into the left brachiocephalic vein or into the left venous angle, which flows forward from the posterior mediastinum, located between the aortic arch and the left mediastinal pleura. This vein serves as a guide for ligating the ductus botallus, which is located below the vein.
V. cava superior is directed from top to bottom, lies behind the right edge of the sternum in the area between the cartilages of the 1st and 3rd ribs and enters the pericardial cavity at the level of the second intercostal space. Here, a usually large v flows into it from behind. Azygos
The upper part of the superior vena cava is located in the tissue of the anterior mediastinum to the right of the ascending aorta and to the left of the right mediastinal pleura. Between the vein and the pleura, the right phrenic nerve is directed from top to bottom, accompanied by a. and v. pericardiacophrenicae. The lower part of the vein is located in the pericardial cavity and lies anterior to the root of the right lung and to the right of the aorta. Lymphatic vessels and anterior mediastinal lymph nodes are adjacent to the extrapericardial part of the superior vena cava, as well as to both brachiocephalic veins. Outside the pericardial cavity, from the mouth of the superior vena cava to the right pulmonary artery there is a sail-shaped ligament, which circularly covers the right pulmonary artery with two sheets and firmly connects the artery with the vein. The veins of the mediastinum and neck flow into the right and left brachiocephalic veins, as well as into the superior vena cava (vv. mediastinales, thymicae, pericar-diacae, bronchiales, tracheales, thoracicae internae, vertebrales and branches of the plexus thyreoi-deus impar).
4. Hypoglossal nerve, its core
The hypoglossal nerve is a motor nerve (Fig. 9.10). Its nucleus is located in the medulla oblongata, while the upper part of the nucleus is located under the bottom of the rhomboid fossa, and the lower part descends along the central canal to the level of the beginning of the intersection of the pyramidal tracts. The nucleus of the XII cranial nerve consists of large multipolar cells and a large number of fibers located between them, with which it is divided into 3 more or less separate cell groups. The axons of the cells of the nucleus of the XII cranial nerve are collected in bundles that penetrate the medulla oblongata and emerge from its anterior lateral sulcus between the inferior olive and the pyramid. Subsequently, they leave the cranial cavity through a special hole in the bone - the canal of the hypoglossal nerve (canalis nervi hypoglossi), located above the lateral edge of the foramen magnum, forming a single trunk.
Coming out of the cranial cavity, the XII cranial nerve passes between the jugular vein and the internal carotid artery, forms the hyoid arch, or loop (ansa cervicalis), passing here in close proximity to the branches of the spinal nerves coming from the three upper cervical segments of the spinal cord and innervating the muscles, attached to the hyoid bone. Subsequently, the hypoglossal nerve turns forward and is divided into lingual branches (rr. linguales), which innervate the muscles of the tongue: hypoglossus (hypoglossus), styloglossus (styloglossus) and genioglossus (genioglossus) and longitudinal and transverse muscles of the tongue (t. longitudinalis and t. transversus linguae).
When the XII nerve is damaged, peripheral paralysis or paresis of the same half of the tongue occurs (Fig. 9.11), while the tongue in the oral cavity shifts to the healthy side, and when protruding from the mouth, it deviates towards the pathological process (the tongue “points to the lesion”). This happens due to the fact that the so called genioglossus of the healthy side pushes the homolateral half of the tongue forward, while the paralyzed half lags behind and the tongue is turned in its direction. The muscles of the paralyzed side of the tongue atrophy and become thinner over time, while the relief of the tongue on the affected side changes - it becomes folded, “geographical”.
1.Muscles of the forearm
Back group
Surface layer
The long radial extensor carpi (m. extensor carpi radialis longus) (Fig. 116, 118) flexes the forearm at the elbow joint, straightens the hand and takes part in its abduction. The muscle has a spindle-shaped shape and is distinguished by a narrow tendon, significantly longer than the abdomen. The upper part of the muscle is covered by the brachioradialis muscle. Its point of origin is located on the lateral epicondyle of the humerus and the lateral intermuscular septum of the brachial fascia, and its attachment point is on the dorsal surface of the base of the second metacarpal bone.
The short radial extensor carpi (m. extensor carpi radialis brevis) straightens the hand, abducting it slightly. This muscle is slightly covered by the extensor carpi radialis longus, originates from the lateral epicondyle of the humerus and the fascia of the forearm, and is attached to the dorsum of the base of the third metacarpal bone.
1 - biceps brachii;
2 - brachialis muscle;
4 - aponeurosis of the biceps brachii muscle;
5 - pronator teres;
6 - brachioradialis muscle;
7 - flexor carpi radialis;
9 - palmaris longus muscle;
10 - superficial flexor of the fingers;
11 - flexor pollicis longus;
12 - short palmaris muscle;
13 - palmar aponeurosis
Muscles of the forearm (front view):
1 - brachialis muscle;
2 - instep support;
3 - tendon of the biceps brachii;
4 - extensor carpi radialis longus;
5 - deep flexor of the fingers;
6 - brachioradialis muscle;
7 - flexor pollicis longus;
8 - pronator teres;
10 - pronator quadratus;
11 - muscle opposing the thumb;
12 - muscle adducting the little finger;
13 - short flexor of the thumb;
14 - tendons of the deep flexor of the fingers;
15 - flexor pollicis longus tendon;
16 - superficial digital flexor tendon
Muscles of the forearm (front view):
1 - pronator teres;
2 - tendon of the biceps brachii;
3 - instep support;
4 - interosseous membrane;
5 - pronator quadratus
Forearm muscles (back view):
1 - brachioradialis muscle;
2 - triceps brachii muscle;
3 - extensor carpi radialis longus;
6 - extensor finger;
8 - extensor of the little finger;
9 - abductor pollicis longus muscle;
10 - short extensor pollicis;
11 - extensor retinaculum;
12 - long extensor of the thumb;
13 - finger extensor tendons
Forearm muscles (back view):
1 - instep support;
2 - deep flexor of the fingers;
3 - abductor pollicis longus muscle;
4 - extensor pollicis longus;
5 - short extensor pollicis;
6 - extensor of the index finger;
7 - extensor retinaculum;
8 - extensor tendons
The extensor digitorum (m. extensor digitorum) straightens the fingers and takes part in the extension of the hand. The muscle belly has a fusiform shape, the direction of the bundles is characterized by a bipinnate shape.
Its point of origin is on the lateral epicondyle of the humerus and the fascia of the forearm. In the middle of its length, the abdomen turns into four tendons, which on the back of the hand turn into tendon stretches, and with their middle part they are attached to the base of the middle phalanges, and with their lateral parts - to the base of the distal phalanges of the II–V fingers.
The extensor of the little finger (m. extensor digiti minimi) (Fig. 118) straightens the little finger. A small fusiform muscle that begins on the lateral epicondyle of the humerus and attaches to the base of the distal phalanx of the fifth finger (little finger).
Extensor carpi ulnaris (m. extensor capiti ulnaris) (Fig. 118) straightens the hand and moves it to the ulnar side. The muscle has a long fusiform belly, begins on the lateral epicondyle of the humerus and fascia of the forearm, and is attached to the base of the dorsal surface of the fifth metacarpal bone.
Deep layer
upinator (m. supinator) (Fig. 116, 117, 119) rotates the forearm outward (supinates) and takes part in straightening the arm at the elbow joint. The muscle has the shape of a thin diamond-shaped plate. Its point of origin is on the crest of the supinator of the ulna, the lateral epicondyle of the humerus and the capsule of the elbow joint. The attachment point for the instep support is located on the lateral, anterior and posterior sides of the upper third of the radius.
The long muscle that abducts the thumb (m. abductor pollicis longus) (Fig. 118, 119) abducts the thumb and takes part in the abduction of the hand. The muscle is partially covered by the extensor digitorum and the short extensor carpi radialis, and has a flat bipinnate belly, which turns into a thin long tendon. It begins on the posterior surface of the ulna and radius and attaches to the base of the first metacarpal bone.
The short extensor pollicis brevis (m. extensor pollicis brevis) (Fig. 118, 119) abducts the thumb and straightens its proximal phalanx. The origin of this muscle is located on the posterior surface of the neck of the radius and the interosseous membrane, the attachment point is on the base of the proximal phalanx of the thumb and the capsule of the first metacarpophalangeal joint.
The long extensor pollicis longus (m. extensor pollicis longus) (Fig. 118, 119) extends the thumb, partially abducting it. The muscle has a fusiform belly and a long tendon. The point of origin is on the posterior surface of the body of the ulna and the interosseous membrane, the attachment point is on the base of the distal phalanx of the thumb.
The extensor of the index finger (m. extensor indicis) (Fig. 119) extends the index finger. This muscle is sometimes absent. It is covered by the extensor digitorum and has a narrow, long, fusiform abdomen.
It begins on the posterior surface of the body of the ulna and the interosseous membrane, and is attached to the dorsal surface of the middle and distal phalanges of the index finger.
2. Male and female urethra
The male urethra, urethra masculina, has an average length of 20–23 cm, and is divided into three parts: prostatic, pars prostatica, membranous, pars membranacea, and spongy, pars spongiosa.
It starts from the bladder with the internal opening of the urethra, ostium urethrae internum, and extends to the external opening of the urethra, ostium urethrae externum. located at the top of the head of the penis. The part of the urethra from the internal opening to the seminal mound, colliculus seminalis, is called the posterior urethra, the distal part is called the anterior urethra. The urethra along its course forms an S-shaped bend: the first, prostatic part, going from top to bottom, forms, with the membranous and the beginning of the spongy part, a convex posterior arc that goes around the pubic symphysis from below - the subpubic curvature; the initial part of the spongy part of the urethra, passing through the section of the penis fixed by ligaments, forms with its hanging part a second knee, convexly directed anteriorly - the prepubic curvature. The division of the urethra into these three parts is determined by the characteristics of the formations that surround it. The prostate part, pars prostatica, penetrates the prostate gland from above, from behind down and forward. It is 3–4 cm long and starts at a narrow part from the internal opening of the urethra (the first bottleneck of the canal). In the middle of its length, an expansion of the urethra is formed (the first expansion). On the posterior wall of the mucous membrane, starting from the uvula of the bladder, uvula vesicae urinariae, which is a longitudinal ridge on the surface of the triangle of the bladder, there is a median fold - the crest of the urethra, crista urethralis. In the middle of its length, the ridge passes into a longitudinally located seed mound, colliculus seminalis: distally this fold reaches the membranous part. At the top of the seminal mound there is a longitudinally located pocket - the prostatic uterus, utriculus prostaticus.
On each side of the crest of the urethra there are the openings of the ejaculatory ducts. On both sides of the seminal mound, between it and the wall of the urethra, the mucous membrane of the urethra forms folds; in the groove limited by them, which is called the prostatic sinus, sinus prostaticus, the mouths of the prostatic ducts, ductuli prostatici, open; Some of the ducts sometimes open on the seminal mound itself.
The membranous part, pars membranacea, is the shortest part of the urethra, has a length of 1.5–2 cm. It is tightly fixed in the urogenital diaphragm, through which it passes. The proximal part of this part of the canal is the narrowest along the entire canal (second bottleneck); the distal section, which passes into the spongy part, becomes wider. The internal opening of the urethra and the proximal part of the prostate are covered by the smooth muscle internal sphincter of the urethra, the fibers of which are a continuation of the muscles of the vesical triangle and are woven into the muscular substance of the prostate gland. The membranous part of the canal and the distal part of the prostate are covered by striated muscle fibers of the sphincter of the urethra, m. sphincter urethrae. These fibers are part of the deep transverse muscle of the perineum, due to which the membranous part is fixed at the outlet of the pelvis and its mobility is very insignificant; this is further enhanced by the fact that part of the muscle fibers of the urogenital diaphragm moves to the prostatic part and to the spongy part and, thus, the membranous part becomes even less mobile.
The spongy part, pars spongiosa, is the longest part of the urethra, has a length of 17–20 cm. It begins with its widest section (second extension), located in the bulb of the penis, the bulbous fossa, and, as stated, reaches the apex of the glans corpus spongiosum of the external opening of the urethra, representing the third bottleneck of the canal. The orifices of the bulbourethral glands open into the posterior (lower) wall of the bulbous part. Proximal to the external opening of the urethra there is an extension located in the sagittal direction - the scaphoid fossa of the urethra. fossa navicularis urethrae, which is the third extension along the canal. The mucous membrane of the upper wall here forms the valve of the scaphoid fossa, valvula fossae navicularis, located transversely on the upper wall of the fossa, thereby separating the pocket open anteriorly. Along the upper wall of the spongy part there are transverse folds in two rows that limit small (0.5 mm) lacunae of the urethra, open anteriorly, lacunae urethrales, into which the tubular-alveolar glands of the urethra open, glandulae urethrales.
Along the entire length of the urethra there are longitudinal folds that cause its extensibility. The lumen of the urethra at the level of the prostatic and membranous parts appears semilunar, convex upward, which depends on the crest and seminiferous mound; along the spongy part, in its proximal part, the lumen has the form of a vertical slit, in the distal part, a transverse slit, and in the region of the head, an S-shaped slit.
The lining of the urethra consists of elastic fibers. A pronounced muscle layer is present only in the prostate and membranous parts; in the spongy part, the mucous membrane is directly fused with spongy tissue, and its smooth muscle fibers belong to the latter. The mucous membrane of the urethra in the prostatic part has a transitional epithelium, in the membranous part it has a multirow prismatic epithelium, at the beginning of the spongy part it has a single layer prismatic epithelium, and throughout the rest of the length it has a multirow prismatic one. Innervation: plexus hypogastricus, lumbosacralis. Blood supply: aa.. pudendae interna et extema.
The female urethra, urethra feminina, starts from the bladder with an internal opening, ostium urethrae internum, and is a tube 3 - 3.5 cm long, slightly curved with a convex posteriorly and bending around the lower edge of the pubic symphysis from below and behind. Outside the period of urine passing through the canal, its front and rear walls are adjacent to one another, but the walls of the canal are distinguished by significant extensibility and its lumen can be stretched to 7 - 8 mm. The posterior wall of the canal is closely connected to the anterior wall of the vagina. When leaving the pelvis, the canal pierces the diaphragma urogenitale (see muscles of the perineum) with its fascia and surrounded by striated voluntary muscle fibers of the sphincter, i.e. sphincter urethrae. The external opening of the canal, ostium urethrae externum, opens into the vestibule of the vagina in front of and above the opening of the vagina and represents a bottleneck of the canal. The wall of the female urethra consists of membranes: muscular, submucosal and mucosal. In the loose tela submucosa, also penetrating into the tunica muscularis, there is a choroid plexus, giving the tissue a cavernous appearance when cut. The mucous membrane, tunica mucosa, lies in longitudinal folds. Numerous mucous glands, glandulae urethrales, open into the canal, especially in the lower parts.
The artery of the female urethra receives from a. vesicalis inferior and a. Pudenda interna. The veins flow through the venous plexus, plexus venosus vesicalis, into v. iliaca interna. Lymphatic vessels from the upper sections of the canal are directed to the nodi lymphatici iliaci, from the lower ones - to the nodi lymphatici inguinales.
Invervation from plexus hypogastrics inferior, nn. splanchnici
